It is known from Italian patent application no 2002A000245, an electrodynamic transducer, which may be used as a pressure sensor in an electric household appliance, and which comprises a casing accommodating a deformable membrane therein sensitive to the hydraulic pressure present on a side of the membrane connected in use, for example, to a tank of an electric household appliance containing a fluid, the level of which is intended to be measured; the membrane carries a ferromagnetic core, operatively connected to an inductor, and a movement thereof thus produces a variation of the resonance frequency of the inductor, which may be detected and processed by a specific processor, usually carried aboard the electric household appliance.
Such a type of sensor, if the liquid level (usually water) in the sump or tank increases over a given limit, is exposed to the risk of being flooded, because the liquid may overflow into the sensor along the tube which connects the sensor to the sump or tank. In order to avoid, or at least limit, this problem, a siphon device is normally arranged between sensor and sump or tank to intercept the liquid overflowing from the tank or sump.
Such a leakage interception device in some cases may not be sufficient to avoid the flooding of the sensor. Furthermore, even if the sensor outputs a signal to the processor of the electric household appliance which may be used to start the pump of the electric household appliance when a given threshold is exceeded, and thus empty the tank or sump before the flooding occurs, the intervention of the pump may be late; furthermore, such a signal threshold should be electronically calibrated, which may be a difficult, long and costly process.